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I have data in an unknown projection to me.

I open it in QGIS and I see that the shapes are ok, but I need to identify the projection in order to merge this data with other stuff.

The points look like WGS84 (EPSG:4326) but without comma.

If a point in WGS84 is like this: (-58,-34)

In this projection the coordinates are something like: (5670000,6120000)

Any ideas?

EDIT: Here there are three pics, showing the situation.

This is the data I'm trying to import, that i don't know what is the projection. Look at the point marked, it corresponds to the central square. Data I'm trying to import

This is my data (it is in lonlat even though it looks deformed). The coordinates shown are from the same central square. My data

This is google maps showing also the central square coordinates. google maps

SOLUTION image, transformed from Campo Inchauspe EPSG:22195 to lonlat. Thanks to mkennedy Solution

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1  
Looks like either NAD83 or possibly some inappropriate UTM zone. What region of the world is this data in? –  Jason Scheirer Feb 28 '13 at 23:59
    
it should be around lon,lat: -58,-34 (that is La Plata, Buenos Aires, Argentina) –  jperelli Mar 1 '13 at 0:01
    
Are you working with projected data, or are you starting with the lat/long coordinates? If the data are projected, you should be able to ID the projection by looking at the metadata. –  Jay Guarneri Mar 1 '13 at 0:16
    
I'm importing a .TAB file that has no projection information. I'm importing it as it would be WGS84, but I see those numbers (5670000,6120000). Around that area, there should be numbers close to (-58,-34) –  jperelli Mar 1 '13 at 0:27
1  
You are right. Sorry @whuber, I posted some pictures now. –  jperelli Mar 1 '13 at 17:18
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1 Answer 1

up vote 4 down vote accepted

I think it's in the Argentina zone 5. It's similar to a UTM zone, except the false easting is (zone number * million + 500000) and the latitude of origin is at -90 rather than the equator. The geographic coordinate reference system ("datum") is the issue as it could be on POSGAR 1994, POSGAR 1998, POSGAR 2007, or an older one like Campo Inchauspe. Here are the EPSG well-known IDs for various possibilities:

Campo Inchauspe  22195
POSGAR 1994   22185
POSGAR 1998   22175
POSGAR 2007   5347
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EPSG:22195 fits perfectly. The other CRS show up in the neighbouring quartiers. –  Andre Joost Mar 1 '13 at 19:48
    
That's right, just as @AndreJoost says. Thank you very much. I couldn't try POSGAR 2007 though, because I couldn't find it in QGIS. I updated the question with the resulting pic. –  jperelli Mar 3 '13 at 16:18
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